The speaker gives his name as Charles, a 24-year-old sitting on a freshly cut log in a forest, a machete in his hand. He does not belong here, in Uganda's Kagombe Forest Reserve. Then again, maybe he does. No less than a presidential order has stopped the evictions of those who've encroached on forest reserves and wetlands. Charles says a government minister recently visited the Kagombe inhabitants. "He told us we can stay," he says, grinning. The minister's cronies have an election coming up, and the best way to placate voters is to promise them land.

Charles and a few other pioneering young villagers moved into the forest in 2006. "We'd been living on our grandparents' property, but there were too many people on the land already," he says. "We heard people talk about how there was free land this way." A migrant group, the Bakiga, had already begun to settle in Kagombe, and when the National Forestry Authority tried to evict them, Uganda's President Yoweri Muse­veni—himself facing reelection—issued the executive order forbidding evictions. Thereupon a few local politicians urged the native Banyoro people, who include Charles and his friends, to grab some forestland as well, lest all of Kagombe wind up inhabited by nonlocals.

Charles and his friends each claimed about seven acres of timberland and began slashing away. They built grass-thatched huts, feed-storage sheds, a road, and a church. They planted corn, bananas, cassava, and Irish potatoes. Then they sent for their wives and began to have more children. Today Charles is one of about 3,000 inhabitants of the forest reserve and has no desire to leave. "We're very well off here," he says.

The forest, meanwhile, sometimes looks like a smoky wasteland, as people use fire to clear the forest for crops. The damage goes beyond the aesthetic: Kagombe serves as one of a series of connective forests that make up a wildlife corridor for chimps and other animals. As Sarah Prinsloo of the Wildlife Conservation Society observes, "The health of the wildlife population in these parks is dependent on corridors like Kagombe." The habitat destruction has contributed to a plunging animal population throughout the region. In Kagombe itself most wildlife has been hunted out.

The forestry authority's sector manager, Patrick Kakeeto, contemplates the devastation with a despairing smile. "They're cutting all of this down," he says. "And we can't touch them. For us, it's a kind of psychoprofessional torture."

How did this land of plenty descend into a perilous free-for-all? Dig deep into its history and it turns out the Albertine Rift has been shaped by mistaken ideas about its ethnic identities. The archaeological and linguistic evidence indicates that by as early as A.D. 500 various peoples had migrated into the region and forged a heterogeneous society that spoke similar Bantu languages and supported itself with both farming and herding. In the 15th century centralized kingdoms such as Bunyoro and Rwanda arose, along with exclusive classes of pastoralists, who distinguished themselves from farmers by their dress and a diet of milk, meat, and blood. Over time these pastoralists became distinct from the rest of the population, and their influence grew.

By the time European explorer John Hanning Speke arrived in the late 19th century, he was astonished by the highly organized kingdoms he encountered, complete with courts and diplomats. He assumed the elite pastoralists, known as Hima or Tutsi, were a superior race of Nilotic people (from what is now Ethiopia) who had invaded the Great Lakes and subjugated what he regarded as the lowly indigenous Bantu farmers, such as Iru or Hutu. "The states of the Great Lakes challenged derogatory racial beliefs about African intellect and ability," says archaeologist Andrew Reid. The idea of a Nilotic invasion was a way to explain away the existence of sophisticated kingdoms in the heart of Africa. The only problem: It wasn't true.

That didn't stop the Tutsi and other elites from embracing the story of their exotic origins to better differentiate themselves from the majority Hutu. And after East Africa was divided between European powers in the late 19th century, the Germans and then the Belgians were only too happy to co-opt what appeared to be the natural social hierarchy and give preference to what they believed to be the superior minority of Tutsi.

Despite the oft-cited physical differences between the two groups—the Tutsi are supposed to be taller, lighter skinned, and thinner lipped than the Hutu—it was so difficult to tell the two apart that by 1933 the Belgians had resorted to issuing identity cards: The 15 percent who owned cattle or had certain physical features were defined as Tutsi, and the rest were Hutu. (Members of one family sometimes ended up in different groups.) These identity cards, officially codifying a caste system that separated one people into two, would be used during the Rwanda genocide to single out who would live and who would be murdered. By the time the colonizers granted the countries independence in the early 1960s, ethnic hostilities between Tutsi and Hutu had already led to waves of killings and retaliatory murders. Today tensions between these two groups continue to play out in the Congo.

But clearly the Rwanda genocide was the result of more than Hutu-Tutsi ethnic hatred. The latter years of the 20th century had brought a sobering recognition that there was in fact not enough for everyone in the Albertine Rift—and with that, catastrophe. An alarming rise in population coincided with a slump in coffee and tea prices in the 1980s, leading to great deprivation; poverty led to an even greater strain on the land. Although it's true that a country like the Netherlands had a population density as high as Rwanda did at this time, it also benefited from mechanized, high-yield agriculture. Rwanda's dependence on traditional subsistence farming meant that the only way to grow more food was to move onto ever more marginal land.

By the mid-1980s every acre of arable land outside the parks was being farmed. Sons were inheriting increasingly smaller plots of land, if any at all. Soils were depleted. Tensions were high. Belgian economists Catherine André and Jean-Philippe Platteau conducted a study of land disputes in one region in Rwanda before the genocide and found that more and more households were struggling to feed themselves on little land. Interviewing residents after the genocide, the researchers found it was not uncommon to hear Rwandans argue that "war is necessary to wipe out an excess of population and to bring numbers into line with the available land resources." Thomas Malthus, the famed English economist who posited that population growth would outstrip the planet's ability to sustain it unless kept in check by starvation, disease, or war, couldn't have put it more succinctly.

André and Platteau do not suggest that the genocide was an inevitable outcome of population pressures, since the killings were clearly instigated by the decisions of power-hungry politicians. But several scholars, including French historian Gérard Prunier, are convinced that a scarcity of land set the stage for the mass killing. In short, the genocide gave landless Hutu the cover they needed to initiate class warfare. "At least part of the reason why it was carried out so thoroughly by the ordinary rank-and-file peasants was the feeling that there were too many people on too little land," Prunier observed in The Rwanda Crisis, "and that with a reduction in their numbers, there would be more for the survivors."

The eastern Congo village of Shasha has become a grim crossroads between major destinations in North Kivu for armed groups seeking land, minerals, and revenge. Mines holding eastern Congo's abundant tin, coltan, and gold are almost exclusively under the control of these roving bands—Hutu and Tutsi paramilitaries, Mai-Mai militias, army soldiers—each descending on Shasha in a macabre rotation, one after another, month after month, in a wave of mayhem.

A woman named Faida weeps quietly as she recalls what happened to her a year ago. She is petite, with fatigued eyes and a voice just above a whisper. In her hands is a letter from her husband, demanding that she leave their house because he feared she might have contracted HIV from the men who raped her.

On that fateful day Faida was on the same road she always took after working in the peanut fields. She would walk an hour and a half to the market at Minova with the peanuts on her back, then return home with firewood. Faida was 32 and of the Hunde ethnic group, married with six children, and for 16 years this had been her routine. She believed no one would attack a woman in broad daylight.

The three men were rebel Hutu. She tried to run, but the load on her back was heavy. The men told her to choose between life and death. Then they dragged her into a cattle field. She lost consciousness.

Today she and her children live with neighbors, and she cannot work. Her husband took another wife. The physical damage done is extensive. "I'm really suffering," she says. "Please help me with medicine, I beg you."

Shasha's population is about 10,000, twice what it was in 1994, and its story is, writ small, that of eastern Congo. A Hunde stronghold since antiquity, Shasha saw an influx of Hutu in the 1930s, when the Belgian occupiers brought them in to work their plantations. Later, in the wake of the 1994 genocide, thousands more Hutu came as refugees. Land disputes became overheated and were frequently resolved at the point of a gun. The area's vast mineral wealth only made things worse. Scarcity and abundance exist here side by side, fueling grievances as well as greed, both spiraling into inexplicable violence against innocents.

Goma women's advocate Marie Gorette estimates that more than 800 females in the village have been raped. They ranged in age, she says, from nine months to 80. One afternoon we sit in a hut while women enter one by one to tell their stories. Odette is strong shouldered and wears a blue print dress. It happened to her just ten days ago. Her 12-year-old son found her unconscious in the cassava fields where she had been working. Justine looks much younger than 28 and has lively eyes. The Congolese Tutsi warlord Laurent Nkunda (under house arrest in Rwanda since 2009) sent CNDP troops into Shasha in 2008. Justine was far from the only one—many of her relatives and neighbors were raped as well. Another woman, 42, tells how Congolese Tutsi rebels barged into her house four years ago, took all the family's money, and raped her. "It's a secret," she says, and I sadly realize she's told me her story only because she thinks I can help her.

Some 200,000 females in the Congo were raped between 1996 and 2008, and more than 8,000 in the eastern provinces of North Kivu and South Kivu in 2009 alone. And despite international attention following a 2009 visit to the region by U.S. Secretary of State Hillary Rodham Clinton, the rapes continue. Just as the "Hutu power" Rwandans sought to eradicate the Tutsi in 1994 by massacring women and children, Shasha's invaders are human heat-seeking missiles aimed at the village's women. "Because it's the corridor, Shasha is the worst place in the region when it comes to mass rapes," says Gorette. "They use rape as a weapon to destroy a generation."

I am somewhere in Rwanda when my car breaks down. A man pulls over to where I'm hovering over the smoking engine and offers to drive me the remaining 70 or so miles to Kigali. "If this were the Congo, you would be in big trouble," he says laughing.

The 41-year-old man's name is Samuel, and though he is from the farming community of Rwamagana, his vocation is carpentry. By the region's standards, Samuel's family is small. "Only four children," he says. "I think that's the ideal size." Schools cost Samuel about $650 per child each term. "But I think education is the solution. Otherwise people have no work. They just resort to having lots of children and stealing to survive." The broad-faced man smiles and says, "I'm very optimistic about our country. The future is indeed bright."

It is no small miracle that the country where the Albertine Rift's anxieties and resentments metastasized into genocide would, less than two decades later, emerge as the region's beacon of hope. Rwanda's President Paul Kagame drove out the Hutu leaders of the massacre and helped set up a Tutsi regime that has been in power ever since. While many credit Kagame with bringing stability and economic growth to this troubled region, several historians have come to view his regime as a repressive autocracy that favors the Tutsi minority. He's come under harsh criticism for human rights abuses against dissidents and for using paramilitary groups to divert mineral riches from eastern Congo to Rwanda. Though Rwanda has largely stopped the direct plunder of resources that occurred during and after Congo's last war, Kagame's plans to build up his country undoubtedly depend on covertly exploiting Congo's mineral wealth.

Still, there's no denying the long list of successes Kagame has piled up in an incredibly impoverished place. Rwanda is now one of the safest and most stable countries in this part of Africa. The roads are paved, the landscape is tidy, and the government has launched an ambitious campaign to preserve what little forest is left in Rwanda. Government programs train poachers for alternative livelihoods. An event known as Kwita Izina has raised awareness of wildlife conservation with an annual ceremony to name every newborn mountain gorilla in Rwanda. A law passed this past June provides compensation for any livestock—or humans—hurt or killed by wildlife. And hundreds of thousands of acres owned by wealthy landowners in the country's Eastern Province were shrewdly redistributed to citizens in 2008, before Kagame's reelection—though the president and other influential cronies continue to own sprawling estates.

Unlike Uganda, where President Museveni has declared its high fertility rate a tool in building a productive workforce, Rwanda is tackling its high fertility rate with aggressive family planning. "When I look at the problem of Rwanda's population, it starts with the high fertility rate among our poor women. And this impacts everything—the environment, the relationship between our people, and the country's development in general," says Jean-Damascène Ntawukuliryayo, the deputy speaker of parliament. "For all the visible progress Rwanda is making, if we don't address this matter, then it will create a bottleneck, and our development will be unsustainable."

Yet even if Rwanda's fertility rate falls below replacement level, as it's projected to do by 2050, its population will still triple beyond what it was before the 1994 genocide. Forty-three percent of Rwandans are under the age of 15; 30 percent are illiterate; 81 percent live in rural areas. To feed its burgeoning population and protect the wildlife still left in its parks, Rwanda will need to figure out how to produce much more food on much less land—a tall order in this part of the world. Even Kagame's strongman government can do only so much so fast.

"The average family of six has little more than half an acre here," says Pierre Rwanyindo Ruzirabwoba, director of Rwanda's Institute of Research and Dialogue for Peace. "And of course those children will have children. Where will they grow crops? That small piece of land has been overworked and is no longer fertile. I'm afraid another war could be around the corner."

Another full-scale war in the heart of the Albertine Rift? It's an awful thing to contemplate. Ruzirabwoba fretfully ponders the way out. High-yield farming techniques, of course. Better job opportunities in the city. And "a good relationship with our neighboring countries."

Then he shrugs and says, "Perhaps some of our people can migrate to the Congo."

Robert Draper is a contributing writer for the magazine who reported on Afghanistan’s opium crop in the February issue. He and photographer Pascal Maitre have collaborated on stories in Somalia and Madagascar. Joel Sartore frequently photographs wildlife for the magazine.